For someone who only speaks the same three words over and over again, Vin Diesel's Groot is a pretty intimidating fella.

Diesel supplies the voice for the sentient tree-creature Groot in "Guardians of the Galaxy," Marvel's oddball space opera heading into theaters next month. And while we won't see Diesel in the flesh when "Guardians" arrives, we have more than enough proof that the actor went above and beyond to get into character.

Case in point: Diesel's new Instagram video showing the "Fast & Furious" star hard at work in the recording booth, repeating the signature "I Am Groot" line over and over again — albeit in Mandarin, not English.

You don't need to speak Mandarin to understand what Diesel's doing here. (Really, you don't; he's just saying "I AM GROOT," because that's literally the only phrase the character can say.) The very image of Diesel on stilts, when he very much does not have to be wearing stilts, growling his soon-to-be iconic line into the microphone, more than explains what we can expect to see from Groot when "Guardians" rocks our faces off in just a few weeks.